Rather than split these into two separate lookups and matches, combine
them into one loop. This will become important when we can guarantee
that we don't have a window where a pending work item isn't discoverable
in either state.
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
fs/io-wq.c | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index a92fbdc8bea3..db150186ce94 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -1072,27 +1072,25 @@ enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
* First check pending list, if we're lucky we can just remove it
* from there. CANCEL_OK means that the work is returned as-new,
* no completion will be posted for it.
- */
- for_each_node(node) {
- struct io_wqe *wqe = wq->wqes[node];
-
- raw_spin_lock(&wqe->lock);
- io_wqe_cancel_pending_work(wqe, &match);
- raw_spin_unlock(&wqe->lock);
- if (match.nr_pending && !match.cancel_all)
- return IO_WQ_CANCEL_OK;
- }
-
- /*
- * Now check if a free (going busy) or busy worker has the work
+ *
+ * Then check if a free (going busy) or busy worker has the work
* currently running. If we find it there, we'll return CANCEL_RUNNING
* as an indication that we attempt to signal cancellation. The
* completion will run normally in this case.
+ *
+ * Do both of these while holding the wqe->lock, to ensure that
+ * we'll find a work item regardless of state.
*/
for_each_node(node) {
struct io_wqe *wqe = wq->wqes[node];
raw_spin_lock(&wqe->lock);
+ io_wqe_cancel_pending_work(wqe, &match);
+ if (match.nr_pending && !match.cancel_all) {
+ raw_spin_unlock(&wqe->lock);
+ return IO_WQ_CANCEL_OK;
+ }
+
io_wqe_cancel_running_work(wqe, &match);
raw_spin_unlock(&wqe->lock);
if (match.nr_running && !match.cancel_all)
--
2.34.1
